YCChiou
Junior Member level 3
parallel coupled line resonator
Dear all;
As we know, parallel coupled-line (PCL) BPF could be electrically equivalent with BPF with series stubs. However, I find a discrepancy between them.
At first, if we plot the equivalent circuit of each coupled stage of a PCL filter, we can obtain one series open stub at both ends of a quarter wavelength transmission line. Next, by cascading n+1 coupled stage to compose of one n-order BPF, we finally would achieve a filter with n+2 series open stubs. For n-order BPF; nevertheless, it only has n series open stubs.
How to interpret this discrepancy? Could everyone explain this? Thanks a lot!
Dear all;
As we know, parallel coupled-line (PCL) BPF could be electrically equivalent with BPF with series stubs. However, I find a discrepancy between them.
At first, if we plot the equivalent circuit of each coupled stage of a PCL filter, we can obtain one series open stub at both ends of a quarter wavelength transmission line. Next, by cascading n+1 coupled stage to compose of one n-order BPF, we finally would achieve a filter with n+2 series open stubs. For n-order BPF; nevertheless, it only has n series open stubs.
How to interpret this discrepancy? Could everyone explain this? Thanks a lot!